From 123abe98037f17750fe17372f3d3ca91e894bf08 Mon Sep 17 00:00:00 2001
From: OpenIM-Gordon <1432970085@qq.com>
Date: Thu, 14 Aug 2025 14:16:50 +0800
Subject: [PATCH] fix: fill in the most recent sendTime for a gap message to
 prevent the client from repeatedly retrieving the same message due to
 sendTime being 0. (#3522)

---
 pkg/common/storage/database/mgo/msg.go | 13 +++++++------
 pkg/common/storage/model/msg.go        |  4 ++++
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/pkg/common/storage/database/mgo/msg.go b/pkg/common/storage/database/mgo/msg.go
index 975e7a0ef..315f4530b 100644
--- a/pkg/common/storage/database/mgo/msg.go
+++ b/pkg/common/storage/database/mgo/msg.go
@@ -5,6 +5,11 @@ import (
 	"fmt"
 	"time"
 
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/primitive"
+	"go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+
 	"github.com/openimsdk/open-im-server/v3/pkg/common/storage/database"
 	"github.com/openimsdk/open-im-server/v3/pkg/common/storage/model"
 	"github.com/openimsdk/protocol/constant"
@@ -14,10 +19,6 @@ import (
 	"github.com/openimsdk/tools/errs"
 	"github.com/openimsdk/tools/utils/datautil"
 	"github.com/openimsdk/tools/utils/jsonutil"
-	"go.mongodb.org/mongo-driver/bson"
-	"go.mongodb.org/mongo-driver/bson/primitive"
-	"go.mongodb.org/mongo-driver/mongo"
-	"go.mongodb.org/mongo-driver/mongo/options"
 )
 
 func NewMsgMongo(db *mongo.Database) (database.Msg, error) {
@@ -1154,7 +1155,7 @@ func (m *MsgMgo) findBeforeDocSendTime(ctx context.Context, docID string, limit
 	if err != nil {
 		return 0, 0, err
 	}
-	for i := len(res) - 1; i > 0; i-- {
+	for i := len(res) - 1; i >= 0; i-- {
 		v := res[i]
 		if v.Msgs != nil && v.Msgs.Msg != nil && v.Msgs.Msg.SendTime > 0 {
 			return v.Msgs.Msg.Seq, v.Msgs.Msg.SendTime, nil
@@ -1169,7 +1170,7 @@ func (m *MsgMgo) findBeforeSendTime(ctx context.Context, conversationID string,
 		limit := int64(-1)
 		if first {
 			first = false
-			limit = m.model.GetMsgIndex(seq)
+			limit = m.model.GetLimitForSingleDoc(seq)
 		}
 		docID := m.model.BuildDocIDByIndex(conversationID, i)
 		msgSeq, msgSendTime, err := m.findBeforeDocSendTime(ctx, docID, limit)
diff --git a/pkg/common/storage/model/msg.go b/pkg/common/storage/model/msg.go
index 9d5b56b42..2bb4882f7 100644
--- a/pkg/common/storage/model/msg.go
+++ b/pkg/common/storage/model/msg.go
@@ -132,6 +132,10 @@ func (*MsgDocModel) GetMsgIndex(seq int64) int64 {
 	return (seq - 1) % singleGocMsgNum
 }
 
+func (*MsgDocModel) GetLimitForSingleDoc(seq int64) int64 {
+	return seq % singleGocMsgNum
+}
+
 func (*MsgDocModel) indexGen(conversationID string, seqSuffix int64) string {
 	return conversationID + ":" + strconv.FormatInt(seqSuffix, 10)
 }